Nippondenso Co., Ltd.

Yuji Otani

Takashi Nagasaka

Mitsuhiro Saitou

Hiroyuki Ban

Takahisa Koyasu

Kengo Oka

Kyoko Nagaoka

A method is provided for easily producing thick multi-layer substrates maintaining highly accurate resistances with little variation. A thick-film resistor 6 on a ceramic substrate 1 is fired at a temperature higher than the temperature of firing a glass insulating layer 2 that is formed thereon in contact therewith. This makes it possible to decrease the change in the resistance in a subsequent high-temperature step of firing the glass insulating layers 2 to 4. Moreover, after the glass insulating layer 2 is formed on the thick-film resistor 6 on the ceramic substrate 1, laser trimming is effected through a window or the glass insulating layer 2 and, thereafter, the glass insulating layers 3 and 4 are formed. This makes it possible to decrease the change in the resistance of the thick-film resistor 6 after laser trimming and to reduce the laser output.

Method of producing thick multi-layer substrates

In a ceramic multi-layer wiring board, a surface conductor layer is made of a copper-based material and an inner conductor in the ceramic multi-layer is a non-copper metal having a melting point higher than a temperature at which the ceramic multi-layer is fired, typically Ag. Cu and Ag form eutectic crystals when firing the surface conductor layer of Cu. This can be prevented by connecting the surface conductor layer and the inner conductor with Ag--Pd or a metal which is different from the materials of the surface wiring layer and the inner conductor and which does not form eutectic crystals with the material of the surface wiring layer at the temperature at which the surface wiring layer is fired.

Ceramic multi-layer wiring board

An electronic circuit device decreases dispersion in the output of the circuit caused by changes in the resistance of the resistors resulting from stress. Resistor positions are selected on the circuit board so that a change in the circuit output caused by a change in resistance of a first resistor group becomes equal to a change caused by a change in resistance caused by a second resistor group, these changes being in opposite directions so as to cancel each other. Alternately, a plurality of resistors are connected to form a composite resistor such that the effect upon resistance of the composite resistor caused by the resistor having decreased resistance is cancelled by the effect upon resistance of the composite resistor caused by a resistor having an increased resistance.

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Okazaki, Japan

Yuji Otani